一例牛源致病型大肠杆菌的分离鉴定

Isolation,Identification and Drug Sensitivity Test of Escherichia coli from Calf

为确定导致黑龙江省哈尔滨市周边某牛场犊牛出现腹泻症状的病原,对病死犊牛进行剖检,无菌采集其相关病料。试验对采集的病料进行病原菌的分离培养,通过革兰氏染色镜检、生化特性考察、PCR鉴定以及动物致病性试验的方式确定病原菌种类,并对分离出来的病原菌进行药敏试验。结果表明:引起该牛场犊牛腹泻的病原菌为含有毒力基因K99的产肠毒素性大肠杆菌(ETEC),该株细菌对氨苄西林、头孢曲松以及头孢噻肟敏感,对环丙沙星、恩诺沙星、左氧氟沙星以及四环素耐药,对庆大霉素和土霉素处于中介状态,说明分离出的大肠杆菌具有较强致病性,用氨苄西林、头孢曲松以及头孢噻肟可以对其引起的疾病进行治疗。

In order to determine what kind of pathogenic bacteria causes diarrhea of calves in a cattle farm around Harbin City,Heilongjiang Province,the dead calves were dissected,and the related disease materials were collected aseptically for isolation and culture of pathogenic bacteria,gram staining microscopy,investigation of biochemical characteristics,PCR identification and animal pathogenicity test.The drug sensitivity test was carried out on the isolated pathogens to provide scientific basis for clinical medication.The results showed that the enterotoxigenic Escherichia coli(ETEC)with virulence gene K99 was the pathogen causing diarrhea of calves.The strain was sensitive to ampicillin,ceftriaxone and cefotaxime,resistant to ciprofloxacin,enrofloxacin,levofloxacin and tetracycline.Gentamicin and oxytetracycline were intermediated.The results indicated that the isolated Escherichia coli had strong pathogenicity,ampicillin,ceftriaxone and cefotaxime could be used to treat the disease.